Photochemical Disproportionation of an AuII Pincer Complex: Synthesis and Structure of an AuI4AuIII4 Macrocycle

The Au­(II) C∧N∧C pincer complex [(C∧N∧C)­Au]2 is stable under thermal conditions but disproportionates on irradiation in solution to give an Au­(I)4Au­(III)4 mixed-valence aggregate with a 20-membered macrocyclic structure, consisting of four linear Au­(I) C–Au–N building blocks, each of which is decorated with a square planar (C∧N∧C)­Au­(III) substituent. In the crystal, the rings are stacked to form solvent-filled channels with an internal diameter of 8.3 Å and a cross-channel AuI···AuI distance of 7.7 Å.